1. Field of the Invention
The present invention relates to an apparatus for controlling music reproduction, the apparatus being suitable for situations where a user listens to the music while performing repetitive exercise such as walking and jogging. The present invention also relates to an apparatus for reproducing music, the apparatus using the apparatus for controlling music reproduction.
2. Description of the Related Art
There has been a conventional apparatus for reproducing music, the apparatus sensing a walking pitch (walking tempo) and modifying music tempo in accordance with the sensed walking tempo to provide a user who is walking while listening to the music with a sense of togetherness between his movements and the music (Japanese Patent Laid-Open Publication No. 2003-85888). There has been another conventional apparatus which, if a difference between the speed of the music in use (music tempo) and an average speed of steps (walking tempo) exceeds a certain value, modifies the speed of the music so that the difference is reduced by a certain ratio (Japanese Patent Laid-Open Publication No. 2003-177749).
The above-described conventional apparatuses only reproduce previously specified music at a modified tempo. In a case where the music is reproduced at a tempo significantly different from the original tempo, as a result, the conventional apparatuses force the user to listen to unnatural music which is quite different from the intention of a performer of the music. Since the conventional apparatuses simply modify a music tempo but fall short of changing user's mood, furthermore, the user gets tired of the music, resulting in his decreased willingness to continue the exercise. In a case where the music data was recorded as waveform data, moreover, a modification to music tempo causes changes in tone pitch and makes the user feel uncomfortable at the music unless the music data is subjected to special signal processing. In a case where the music was recorded as performance data such as MIDI (Musical Instrument Digital Interface) data, although a modification to music tempo does not cause changes in tone pitch, the music data recorded as performance data has less musical richness than the music data recorded as waveform data.
There has also been an apparatus called running pacemaker (a conventional art described in Japanese Patent Laid-Open Publication No. 2001-299980). This apparatus allows a user to specify the highest and lowest values of his allowable pulse, and his desired pace (running pitch), so that the output pace of electronic tones output by a variable frequency circuit decreases when his pulse exceeds the specified highest value, while the output pace of electronic tones increases when his pulse falls below the lowest value.
Furthermore, there has been a conventional exercise support apparatus which uses music data instead of electronic tones, and modifies tempo (music tempo) through the use of a sensor for sensing motion tempo (running tempo) (see Japanese Patent Laid-Open Publication No. 2001-299980). More specifically, this exercise support apparatus generates a function of target pulse time in accordance with values specified by the user, so that a modified tempo is obtained by adding a correction amount obtained by multiplying a difference ΔH(t) between a user's pulse and a target pulse by the original tempo and a coefficient A to a value obtained by multiplying the exercise tempo by a coefficient D. As a result, the exercise support apparatus achieves control of the user's pulse. Letting the coefficient A=0, the music tempo is modified to agree with the running tempo.
There has also been a conventional apparatus for reproducing music, the apparatus leading user's heart rate to an ideal heart rate by measuring user's heart rate to modify the speed of music (music tempo) when the difference between the measured heart rate and an ideal heart rate derived from user's information exceeds a certain value (see Japanese Patent Laid-Open Publication No. 2003-177750). In these above-described conventional arts as well, however, these apparatuses only reproduce previously specified music data at a modified tempo.
Furthermore, there has been an automatic performance apparatus which senses user's pulse to calculate the percentage of exercise load on the basis of the sensed pulse. In accordance with the percentage of exercise load of 70% to 100%, the automatic performance apparatus specifies a tempo coefficient P=1.0 to 0.7, selects one of automatic performance data files each of which has an original tempo slowing down in the order of the tempo coefficient P and is stored in correspondence with the tempo coefficient P, and reproduces the selected automatic performance data (see the second embodiment of Japanese Patent Laid-Open Publication No. H10-63265). As the exercise load rate increases, the automatic performance apparatus selects an automatic performance data file having a slower reproduction tempo (music tempo), resulting in the user also slowing down his jogging pace in harmony with the decreased music tempo. At each change in the tempo coefficient P, in addition, the automatic performance apparatus stops the currently reproduced song before starting a newly selected song from the beginning of the song. In order to switch to a newly selected song, furthermore, the automatic performance apparatus can also cross-fade the currently reproduced song and the newly selected song, or complete, in a more natural manner, the automatic performance of the currently reproduced song until the end of the song before starting the reproduction of the newly selected song.
As a result, the automatic performance apparatus switches the automatic performance data in accordance with exercise load rate but reproduces songs at their respective original tempos. From a user's point of view, however, the user only recognizes the current exercise load rate from the music tempo, but this apparatus does not affect his walking pitch in order to lead to the optimal exercise load rate. Since the reproduction tempo does not necessarily agree with the user's walking tempo, more specifically, exercise while listening to such music makes the user feel uncomfortable. If there is no change in the user's exercise load rate, furthermore, there is no change in the tempo coefficient P as well, resulting in the termination of the automatic performance at the end of the reproduction of the currently reproduced song.
There has also been a distribution apparatus (see Japanese Patent Laid-Open Publication No. 2003-108154). This distribution apparatus transmits time TC elapsed from the beginning of exercise, an exercise intensity m, a heart rate S, a walking tempo T to a distribution site every time a user walks for a certain distance, while the distribution site searches for song data having a tempo (music tempo) providing the user with a most suitable exercise load, distributes the found song data to allow a tone generator of a terminal apparatus to reproduce the song data. More specifically, the distribution is done such that a load heart rate F corresponding to the exercise intensity m is read out from a heart rate historical table TBL1 to multiply the walking tempo T by a tempo increase/decrease coefficient C corresponding to a difference Δd between the load heart rate F and the user's heart rate S to obtain a load tempo TMP to retrieve song data having a tempo which approximately agrees with the load tempo TMP from a database.
Therefore, this conventional art realizes reproduction of song data having a tempo which approximately agrees with a walking tempo providing a user with an optimal exercise load. However, this conventional art requires access to a distribution site to download the song data, demanding a prolonged process delay for switching song data. In addition, both the intervals between the measurement of user's heart rate and the intervals between the switching of music data are the time required for the user to walk for a certain distance. In order to quickly respond to the changes in heart rate, as a result, the certain distance has to be short. If there is no change in heart rate over some period of time, however, reproduction of the same song from the beginning will be reiterated over the period of time with short intervals. In addition, intervals between the switching can vary, depending on user's walking tempo. Moreover, this conventional art requires a sensor for measuring the walking tempo T. Furthermore, this conventional art has not yet considered how the song data files are stored and how a song data file having a tempo which approximately agrees with the load tempo TMP is retrieved by the distribution site.
There has also been a conventional art for prompting a user to do exercise which naturally quickens the user's heart rate (see Japanese Patent Laid-Open Publication No. 2005-87731). When the user's instant heart rate falls below the lowest heart rate of a target exercise range during his exercise, more specifically, this conventional art provides the user with a song of a rhythm faster than the current instant heart rate (beat falling within a range from the lowest heart rate to a mean heart rate of the target exercise range) to make the user recognize his low heart rate, prompting the user to do exercise in harmony with the song having the rhythm faster than the current heart rate. However, the rhythm (beat) of a song merely tells the user that his instant heart rate is lower than the lowest heart rate of the target exercise range, but will not be modified with consideration given to walking tempo or the like. Therefore, the beat of the song does not agree with user's walking tempo.